Add six==1.3.0 to requirements.txt

Signed-off-by: Mike Neilsen <mneilsen@acm.org>
Create tests module for setuptools test support

Run test suite via

  python setup.py test

Signed-off-by: Mike Neilsen <mneilsen@acm.org>
Merge pull request #18 from mneilsen/master

Minor fixes: requirements.txt, setuptools test support